Protein engineering and directed evolution applications often use saturation mutagenesis to create a library of variants for screening. However, saturation mutagenesis by error-prone PCR (epPCR) suffers from amplification biases and incomplete access to the codon mutational space. Site Saturation Variant Libraries (SSVLs) offer a synthetic alternative free of the technical limitations of epPCR. Here, the performance of a Twist SSVL was benchmarked against an epPCR library using a glucose activation assay in yeast. Compared to epPCR, the SSVL produced greater variant representation while also simplifying downstream validation steps by providing access to the complete variant diversity.